//===- X86ISelDAGToDAG.cpp - A DAG pattern matching inst selector for X86 -===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file defines a DAG pattern matching instruction selector for X86, // converting from a legalized dag to a X86 dag. // //===----------------------------------------------------------------------===// #define DEBUG_TYPE "x86-isel" #include "X86.h" #include "X86InstrBuilder.h" #include "X86ISelLowering.h" #include "X86MachineFunctionInfo.h" #include "X86RegisterInfo.h" #include "X86Subtarget.h" #include "X86TargetMachine.h" #include "llvm/GlobalValue.h" #include "llvm/Instructions.h" #include "llvm/Intrinsics.h" #include "llvm/Support/CFG.h" #include "llvm/Type.h" #include "llvm/CodeGen/MachineConstantPool.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/SelectionDAGISel.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Support/Compiler.h" #include "llvm/Support/Debug.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/Streams.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/Statistic.h" #include #include using namespace llvm; STATISTIC(NumFPKill , "Number of FP_REG_KILL instructions added"); STATISTIC(NumLoadMoved, "Number of loads moved below TokenFactor"); //===----------------------------------------------------------------------===// // Pattern Matcher Implementation //===----------------------------------------------------------------------===// namespace { /// X86ISelAddressMode - This corresponds to X86AddressMode, but uses /// SDValue's instead of register numbers for the leaves of the matched /// tree. struct X86ISelAddressMode { enum { RegBase, FrameIndexBase } BaseType; struct { // This is really a union, discriminated by BaseType! SDValue Reg; int FrameIndex; } Base; bool isRIPRel; // RIP as base? unsigned Scale; SDValue IndexReg; unsigned Disp; GlobalValue *GV; Constant *CP; const char *ES; int JT; unsigned Align; // CP alignment. X86ISelAddressMode() : BaseType(RegBase), isRIPRel(false), Scale(1), IndexReg(), Disp(0), GV(0), CP(0), ES(0), JT(-1), Align(0) { } void dump() { cerr << "X86ISelAddressMode " << this << "\n"; cerr << "Base.Reg "; if (Base.Reg.getNode() != 0) Base.Reg.getNode()->dump(); else cerr << "nul"; cerr << " Base.FrameIndex " << Base.FrameIndex << "\n"; cerr << "isRIPRel " << isRIPRel << " Scale" << Scale << "\n"; cerr << "IndexReg "; if (IndexReg.getNode() != 0) IndexReg.getNode()->dump(); else cerr << "nul"; cerr << " Disp " << Disp << "\n"; cerr << "GV "; if (GV) GV->dump(); else cerr << "nul"; cerr << " CP "; if (CP) CP->dump(); else cerr << "nul"; cerr << "\n"; cerr << "ES "; if (ES) cerr << ES; else cerr << "nul"; cerr << " JT" << JT << " Align" << Align << "\n"; } }; } namespace { //===--------------------------------------------------------------------===// /// ISel - X86 specific code to select X86 machine instructions for /// SelectionDAG operations. /// class VISIBILITY_HIDDEN X86DAGToDAGISel : public SelectionDAGISel { /// ContainsFPCode - Every instruction we select that uses or defines a FP /// register should set this to true. bool ContainsFPCode; /// TM - Keep a reference to X86TargetMachine. /// X86TargetMachine &TM; /// X86Lowering - This object fully describes how to lower LLVM code to an /// X86-specific SelectionDAG. X86TargetLowering X86Lowering; /// Subtarget - Keep a pointer to the X86Subtarget around so that we can /// make the right decision when generating code for different targets. const X86Subtarget *Subtarget; /// GlobalBaseReg - keeps track of the virtual register mapped onto global /// base register. unsigned GlobalBaseReg; /// CurBB - Current BB being isel'd. /// MachineBasicBlock *CurBB; public: X86DAGToDAGISel(X86TargetMachine &tm, bool fast) : SelectionDAGISel(X86Lowering, fast), ContainsFPCode(false), TM(tm), X86Lowering(*TM.getTargetLowering()), Subtarget(&TM.getSubtarget()) {} virtual bool runOnFunction(Function &Fn) { // Make sure we re-emit a set of the global base reg if necessary GlobalBaseReg = 0; return SelectionDAGISel::runOnFunction(Fn); } virtual const char *getPassName() const { return "X86 DAG->DAG Instruction Selection"; } /// InstructionSelect - This callback is invoked by /// SelectionDAGISel when it has created a SelectionDAG for us to codegen. virtual void InstructionSelect(); /// InstructionSelectPostProcessing - Post processing of selected and /// scheduled basic blocks. virtual void InstructionSelectPostProcessing(); virtual void EmitFunctionEntryCode(Function &Fn, MachineFunction &MF); virtual bool CanBeFoldedBy(SDNode *N, SDNode *U, SDNode *Root) const; // Include the pieces autogenerated from the target description. #include "X86GenDAGISel.inc" private: SDNode *Select(SDValue N); bool MatchAddress(SDValue N, X86ISelAddressMode &AM, bool isRoot = true, unsigned Depth = 0); bool MatchAddressBase(SDValue N, X86ISelAddressMode &AM, bool isRoot, unsigned Depth); bool SelectAddr(SDValue Op, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp); bool SelectLEAAddr(SDValue Op, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp); bool SelectScalarSSELoad(SDValue Op, SDValue Pred, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &InChain, SDValue &OutChain); bool TryFoldLoad(SDValue P, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp); void PreprocessForRMW(); void PreprocessForFPConvert(); /// SelectInlineAsmMemoryOperand - Implement addressing mode selection for /// inline asm expressions. virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode, std::vector &OutOps); void EmitSpecialCodeForMain(MachineBasicBlock *BB, MachineFrameInfo *MFI); inline void getAddressOperands(X86ISelAddressMode &AM, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp) { Base = (AM.BaseType == X86ISelAddressMode::FrameIndexBase) ? CurDAG->getTargetFrameIndex(AM.Base.FrameIndex, TLI.getPointerTy()) : AM.Base.Reg; Scale = getI8Imm(AM.Scale); Index = AM.IndexReg; // These are 32-bit even in 64-bit mode since RIP relative offset // is 32-bit. if (AM.GV) Disp = CurDAG->getTargetGlobalAddress(AM.GV, MVT::i32, AM.Disp); else if (AM.CP) Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i32, AM.Align, AM.Disp); else if (AM.ES) Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i32); else if (AM.JT != -1) Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i32); else Disp = getI32Imm(AM.Disp); } /// getI8Imm - Return a target constant with the specified value, of type /// i8. inline SDValue getI8Imm(unsigned Imm) { return CurDAG->getTargetConstant(Imm, MVT::i8); } /// getI16Imm - Return a target constant with the specified value, of type /// i16. inline SDValue getI16Imm(unsigned Imm) { return CurDAG->getTargetConstant(Imm, MVT::i16); } /// getI32Imm - Return a target constant with the specified value, of type /// i32. inline SDValue getI32Imm(unsigned Imm) { return CurDAG->getTargetConstant(Imm, MVT::i32); } /// getGlobalBaseReg - insert code into the entry mbb to materialize the PIC /// base register. Return the virtual register that holds this value. SDNode *getGlobalBaseReg(); /// getTruncateTo8Bit - return an SDNode that implements a subreg based /// truncate of the specified operand to i8. This can be done with tablegen, /// except that this code uses MVT::Flag in a tricky way that happens to /// improve scheduling in some cases. SDNode *getTruncateTo8Bit(SDValue N0); #ifndef NDEBUG unsigned Indent; #endif }; } /// findFlagUse - Return use of MVT::Flag value produced by the specified /// SDNode. /// static SDNode *findFlagUse(SDNode *N) { unsigned FlagResNo = N->getNumValues()-1; for (SDNode::use_iterator I = N->use_begin(), E = N->use_end(); I != E; ++I) { SDNode *User = *I; for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) { SDValue Op = User->getOperand(i); if (Op.getNode() == N && Op.getResNo() == FlagResNo) return User; } } return NULL; } /// findNonImmUse - Return true by reference in "found" if "Use" is an /// non-immediate use of "Def". This function recursively traversing /// up the operand chain ignoring certain nodes. static void findNonImmUse(SDNode *Use, SDNode* Def, SDNode *ImmedUse, SDNode *Root, bool &found, SmallPtrSet &Visited) { if (found || Use->getNodeId() > Def->getNodeId() || !Visited.insert(Use)) return; for (unsigned i = 0, e = Use->getNumOperands(); !found && i != e; ++i) { SDNode *N = Use->getOperand(i).getNode(); if (N == Def) { if (Use == ImmedUse || Use == Root) continue; // We are not looking for immediate use. assert(N != Root); found = true; break; } // Traverse up the operand chain. findNonImmUse(N, Def, ImmedUse, Root, found, Visited); } } /// isNonImmUse - Start searching from Root up the DAG to check is Def can /// be reached. Return true if that's the case. However, ignore direct uses /// by ImmedUse (which would be U in the example illustrated in /// CanBeFoldedBy) and by Root (which can happen in the store case). /// FIXME: to be really generic, we should allow direct use by any node /// that is being folded. But realisticly since we only fold loads which /// have one non-chain use, we only need to watch out for load/op/store /// and load/op/cmp case where the root (store / cmp) may reach the load via /// its chain operand. static inline bool isNonImmUse(SDNode *Root, SDNode *Def, SDNode *ImmedUse) { SmallPtrSet Visited; bool found = false; findNonImmUse(Root, Def, ImmedUse, Root, found, Visited); return found; } bool X86DAGToDAGISel::CanBeFoldedBy(SDNode *N, SDNode *U, SDNode *Root) const { if (Fast) return false; // If Root use can somehow reach N through a path that that doesn't contain // U then folding N would create a cycle. e.g. In the following // diagram, Root can reach N through X. If N is folded into into Root, then // X is both a predecessor and a successor of U. // // [N*] // // ^ ^ // // / \ // // [U*] [X]? // // ^ ^ // // \ / // // \ / // // [Root*] // // // * indicates nodes to be folded together. // // If Root produces a flag, then it gets (even more) interesting. Since it // will be "glued" together with its flag use in the scheduler, we need to // check if it might reach N. // // [N*] // // ^ ^ // // / \ // // [U*] [X]? // // ^ ^ // // \ \ // // \ | // // [Root*] | // // ^ | // // f | // // | / // // [Y] / // // ^ / // // f / // // | / // // [FU] // // // If FU (flag use) indirectly reaches N (the load), and Root folds N // (call it Fold), then X is a predecessor of FU and a successor of // Fold. But since Fold and FU are flagged together, this will create // a cycle in the scheduling graph. MVT VT = Root->getValueType(Root->getNumValues()-1); while (VT == MVT::Flag) { SDNode *FU = findFlagUse(Root); if (FU == NULL) break; Root = FU; VT = Root->getValueType(Root->getNumValues()-1); } return !isNonImmUse(Root, N, U); } /// MoveBelowTokenFactor - Replace TokenFactor operand with load's chain operand /// and move load below the TokenFactor. Replace store's chain operand with /// load's chain result. static void MoveBelowTokenFactor(SelectionDAG *CurDAG, SDValue Load, SDValue Store, SDValue TF) { SmallVector Ops; for (unsigned i = 0, e = TF.getNode()->getNumOperands(); i != e; ++i) if (Load.getNode() == TF.getOperand(i).getNode()) Ops.push_back(Load.getOperand(0)); else Ops.push_back(TF.getOperand(i)); CurDAG->UpdateNodeOperands(TF, &Ops[0], Ops.size()); CurDAG->UpdateNodeOperands(Load, TF, Load.getOperand(1), Load.getOperand(2)); CurDAG->UpdateNodeOperands(Store, Load.getValue(1), Store.getOperand(1), Store.getOperand(2), Store.getOperand(3)); } /// isRMWLoad - Return true if N is a load that's part of RMW sub-DAG. /// static bool isRMWLoad(SDValue N, SDValue Chain, SDValue Address, SDValue &Load) { if (N.getOpcode() == ISD::BIT_CONVERT) N = N.getOperand(0); LoadSDNode *LD = dyn_cast(N); if (!LD || LD->isVolatile()) return false; if (LD->getAddressingMode() != ISD::UNINDEXED) return false; ISD::LoadExtType ExtType = LD->getExtensionType(); if (ExtType != ISD::NON_EXTLOAD && ExtType != ISD::EXTLOAD) return false; if (N.hasOneUse() && N.getOperand(1) == Address && N.getNode()->isOperandOf(Chain.getNode())) { Load = N; return true; } return false; } /// MoveBelowCallSeqStart - Replace CALLSEQ_START operand with load's chain /// operand and move load below the call's chain operand. static void MoveBelowCallSeqStart(SelectionDAG *CurDAG, SDValue Load, SDValue Call, SDValue Chain) { SmallVector Ops; for (unsigned i = 0, e = Chain.getNode()->getNumOperands(); i != e; ++i) if (Load.getNode() == Chain.getOperand(i).getNode()) Ops.push_back(Load.getOperand(0)); else Ops.push_back(Chain.getOperand(i)); CurDAG->UpdateNodeOperands(Chain, &Ops[0], Ops.size()); CurDAG->UpdateNodeOperands(Load, Call.getOperand(0), Load.getOperand(1), Load.getOperand(2)); Ops.clear(); Ops.push_back(SDValue(Load.getNode(), 1)); for (unsigned i = 1, e = Call.getNode()->getNumOperands(); i != e; ++i) Ops.push_back(Call.getOperand(i)); CurDAG->UpdateNodeOperands(Call, &Ops[0], Ops.size()); } /// isCalleeLoad - Return true if call address is a load and it can be /// moved below CALLSEQ_START and the chains leading up to the call. /// Return the CALLSEQ_START by reference as a second output. static bool isCalleeLoad(SDValue Callee, SDValue &Chain) { if (Callee.getNode() == Chain.getNode() || !Callee.hasOneUse()) return false; LoadSDNode *LD = dyn_cast(Callee.getNode()); if (!LD || LD->isVolatile() || LD->getAddressingMode() != ISD::UNINDEXED || LD->getExtensionType() != ISD::NON_EXTLOAD) return false; // Now let's find the callseq_start. while (Chain.getOpcode() != ISD::CALLSEQ_START) { if (!Chain.hasOneUse()) return false; Chain = Chain.getOperand(0); } return Chain.getOperand(0).getNode() == Callee.getNode(); } /// PreprocessForRMW - Preprocess the DAG to make instruction selection better. /// This is only run if not in -fast mode (aka -O0). /// This allows the instruction selector to pick more read-modify-write /// instructions. This is a common case: /// /// [Load chain] /// ^ /// | /// [Load] /// ^ ^ /// | | /// / \- /// / | /// [TokenFactor] [Op] /// ^ ^ /// | | /// \ / /// \ / /// [Store] /// /// The fact the store's chain operand != load's chain will prevent the /// (store (op (load))) instruction from being selected. We can transform it to: /// /// [Load chain] /// ^ /// | /// [TokenFactor] /// ^ /// | /// [Load] /// ^ ^ /// | | /// | \- /// | | /// | [Op] /// | ^ /// | | /// \ / /// \ / /// [Store] void X86DAGToDAGISel::PreprocessForRMW() { for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(), E = CurDAG->allnodes_end(); I != E; ++I) { if (I->getOpcode() == X86ISD::CALL) { /// Also try moving call address load from outside callseq_start to just /// before the call to allow it to be folded. /// /// [Load chain] /// ^ /// | /// [Load] /// ^ ^ /// | | /// / \-- /// / | ///[CALLSEQ_START] | /// ^ | /// | | /// [LOAD/C2Reg] | /// | | /// \ / /// \ / /// [CALL] SDValue Chain = I->getOperand(0); SDValue Load = I->getOperand(1); if (!isCalleeLoad(Load, Chain)) continue; MoveBelowCallSeqStart(CurDAG, Load, SDValue(I, 0), Chain); ++NumLoadMoved; continue; } if (!ISD::isNON_TRUNCStore(I)) continue; SDValue Chain = I->getOperand(0); if (Chain.getNode()->getOpcode() != ISD::TokenFactor) continue; SDValue N1 = I->getOperand(1); SDValue N2 = I->getOperand(2); if ((N1.getValueType().isFloatingPoint() && !N1.getValueType().isVector()) || !N1.hasOneUse()) continue; bool RModW = false; SDValue Load; unsigned Opcode = N1.getNode()->getOpcode(); switch (Opcode) { case ISD::ADD: case ISD::MUL: case ISD::AND: case ISD::OR: case ISD::XOR: case ISD::ADDC: case ISD::ADDE: case ISD::VECTOR_SHUFFLE: { SDValue N10 = N1.getOperand(0); SDValue N11 = N1.getOperand(1); RModW = isRMWLoad(N10, Chain, N2, Load); if (!RModW) RModW = isRMWLoad(N11, Chain, N2, Load); break; } case ISD::SUB: case ISD::SHL: case ISD::SRA: case ISD::SRL: case ISD::ROTL: case ISD::ROTR: case ISD::SUBC: case ISD::SUBE: case X86ISD::SHLD: case X86ISD::SHRD: { SDValue N10 = N1.getOperand(0); RModW = isRMWLoad(N10, Chain, N2, Load); break; } } if (RModW) { MoveBelowTokenFactor(CurDAG, Load, SDValue(I, 0), Chain); ++NumLoadMoved; } } } /// PreprocessForFPConvert - Walk over the dag lowering fpround and fpextend /// nodes that target the FP stack to be store and load to the stack. This is a /// gross hack. We would like to simply mark these as being illegal, but when /// we do that, legalize produces these when it expands calls, then expands /// these in the same legalize pass. We would like dag combine to be able to /// hack on these between the call expansion and the node legalization. As such /// this pass basically does "really late" legalization of these inline with the /// X86 isel pass. void X86DAGToDAGISel::PreprocessForFPConvert() { for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(), E = CurDAG->allnodes_end(); I != E; ) { SDNode *N = I++; // Preincrement iterator to avoid invalidation issues. if (N->getOpcode() != ISD::FP_ROUND && N->getOpcode() != ISD::FP_EXTEND) continue; // If the source and destination are SSE registers, then this is a legal // conversion that should not be lowered. MVT SrcVT = N->getOperand(0).getValueType(); MVT DstVT = N->getValueType(0); bool SrcIsSSE = X86Lowering.isScalarFPTypeInSSEReg(SrcVT); bool DstIsSSE = X86Lowering.isScalarFPTypeInSSEReg(DstVT); if (SrcIsSSE && DstIsSSE) continue; if (!SrcIsSSE && !DstIsSSE) { // If this is an FPStack extension, it is a noop. if (N->getOpcode() == ISD::FP_EXTEND) continue; // If this is a value-preserving FPStack truncation, it is a noop. if (N->getConstantOperandVal(1)) continue; } // Here we could have an FP stack truncation or an FPStack <-> SSE convert. // FPStack has extload and truncstore. SSE can fold direct loads into other // operations. Based on this, decide what we want to do. MVT MemVT; if (N->getOpcode() == ISD::FP_ROUND) MemVT = DstVT; // FP_ROUND must use DstVT, we can't do a 'trunc load'. else MemVT = SrcIsSSE ? SrcVT : DstVT; SDValue MemTmp = CurDAG->CreateStackTemporary(MemVT); // FIXME: optimize the case where the src/dest is a load or store? SDValue Store = CurDAG->getTruncStore(CurDAG->getEntryNode(), N->getOperand(0), MemTmp, NULL, 0, MemVT); SDValue Result = CurDAG->getExtLoad(ISD::EXTLOAD, DstVT, Store, MemTmp, NULL, 0, MemVT); // We're about to replace all uses of the FP_ROUND/FP_EXTEND with the // extload we created. This will cause general havok on the dag because // anything below the conversion could be folded into other existing nodes. // To avoid invalidating 'I', back it up to the convert node. --I; CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Result); // Now that we did that, the node is dead. Increment the iterator to the // next node to process, then delete N. ++I; CurDAG->DeleteNode(N); } } /// InstructionSelectBasicBlock - This callback is invoked by SelectionDAGISel /// when it has created a SelectionDAG for us to codegen. void X86DAGToDAGISel::InstructionSelect() { CurBB = BB; // BB can change as result of isel. DEBUG(BB->dump()); if (!Fast) PreprocessForRMW(); // FIXME: This should only happen when not -fast. PreprocessForFPConvert(); // Codegen the basic block. #ifndef NDEBUG DOUT << "===== Instruction selection begins:\n"; Indent = 0; #endif SelectRoot(); #ifndef NDEBUG DOUT << "===== Instruction selection ends:\n"; #endif CurDAG->RemoveDeadNodes(); } void X86DAGToDAGISel::InstructionSelectPostProcessing() { // If we are emitting FP stack code, scan the basic block to determine if this // block defines any FP values. If so, put an FP_REG_KILL instruction before // the terminator of the block. // Note that FP stack instructions are used in all modes for long double, // so we always need to do this check. // Also note that it's possible for an FP stack register to be live across // an instruction that produces multiple basic blocks (SSE CMOV) so we // must check all the generated basic blocks. // Scan all of the machine instructions in these MBBs, checking for FP // stores. (RFP32 and RFP64 will not exist in SSE mode, but RFP80 might.) MachineFunction::iterator MBBI = CurBB; MachineFunction::iterator EndMBB = BB; ++EndMBB; for (; MBBI != EndMBB; ++MBBI) { MachineBasicBlock *MBB = MBBI; // If this block returns, ignore it. We don't want to insert an FP_REG_KILL // before the return. if (!MBB->empty()) { MachineBasicBlock::iterator EndI = MBB->end(); --EndI; if (EndI->getDesc().isReturn()) continue; } bool ContainsFPCode = false; for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end(); !ContainsFPCode && I != E; ++I) { if (I->getNumOperands() != 0 && I->getOperand(0).isRegister()) { const TargetRegisterClass *clas; for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op) { if (I->getOperand(op).isRegister() && I->getOperand(op).isDef() && TargetRegisterInfo::isVirtualRegister(I->getOperand(op).getReg()) && ((clas = RegInfo->getRegClass(I->getOperand(0).getReg())) == X86::RFP32RegisterClass || clas == X86::RFP64RegisterClass || clas == X86::RFP80RegisterClass)) { ContainsFPCode = true; break; } } } } // Check PHI nodes in successor blocks. These PHI's will be lowered to have // a copy of the input value in this block. In SSE mode, we only care about // 80-bit values. if (!ContainsFPCode) { // Final check, check LLVM BB's that are successors to the LLVM BB // corresponding to BB for FP PHI nodes. const BasicBlock *LLVMBB = BB->getBasicBlock(); const PHINode *PN; for (succ_const_iterator SI = succ_begin(LLVMBB), E = succ_end(LLVMBB); !ContainsFPCode && SI != E; ++SI) { for (BasicBlock::const_iterator II = SI->begin(); (PN = dyn_cast(II)); ++II) { if (PN->getType()==Type::X86_FP80Ty || (!Subtarget->hasSSE1() && PN->getType()->isFloatingPoint()) || (!Subtarget->hasSSE2() && PN->getType()==Type::DoubleTy)) { ContainsFPCode = true; break; } } } } // Finally, if we found any FP code, emit the FP_REG_KILL instruction. if (ContainsFPCode) { BuildMI(*MBB, MBBI->getFirstTerminator(), TM.getInstrInfo()->get(X86::FP_REG_KILL)); ++NumFPKill; } } } /// EmitSpecialCodeForMain - Emit any code that needs to be executed only in /// the main function. void X86DAGToDAGISel::EmitSpecialCodeForMain(MachineBasicBlock *BB, MachineFrameInfo *MFI) { const TargetInstrInfo *TII = TM.getInstrInfo(); if (Subtarget->isTargetCygMing()) BuildMI(BB, TII->get(X86::CALLpcrel32)).addExternalSymbol("__main"); } void X86DAGToDAGISel::EmitFunctionEntryCode(Function &Fn, MachineFunction &MF) { // If this is main, emit special code for main. MachineBasicBlock *BB = MF.begin(); if (Fn.hasExternalLinkage() && Fn.getName() == "main") EmitSpecialCodeForMain(BB, MF.getFrameInfo()); } /// MatchAddress - Add the specified node to the specified addressing mode, /// returning true if it cannot be done. This just pattern matches for the /// addressing mode. bool X86DAGToDAGISel::MatchAddress(SDValue N, X86ISelAddressMode &AM, bool isRoot, unsigned Depth) { DOUT << "MatchAddress: "; DEBUG(AM.dump()); // Limit recursion. if (Depth > 5) return MatchAddressBase(N, AM, isRoot, Depth); // RIP relative addressing: %rip + 32-bit displacement! if (AM.isRIPRel) { if (!AM.ES && AM.JT != -1 && N.getOpcode() == ISD::Constant) { int64_t Val = cast(N)->getSignExtended(); if (isInt32(AM.Disp + Val)) { AM.Disp += Val; return false; } } return true; } int id = N.getNode()->getNodeId(); bool AlreadySelected = isSelected(id); // Already selected, not yet replaced. switch (N.getOpcode()) { default: break; case ISD::Constant: { int64_t Val = cast(N)->getSignExtended(); if (isInt32(AM.Disp + Val)) { AM.Disp += Val; return false; } break; } case X86ISD::Wrapper: { DOUT << "Wrapper: 64bit " << Subtarget->is64Bit(); DOUT << " AM "; DEBUG(AM.dump()); DOUT << "\n"; DOUT << "AlreadySelected " << AlreadySelected << "\n"; bool is64Bit = Subtarget->is64Bit(); // Under X86-64 non-small code model, GV (and friends) are 64-bits. // Also, base and index reg must be 0 in order to use rip as base. if (is64Bit && (TM.getCodeModel() != CodeModel::Small || AM.Base.Reg.getNode() || AM.IndexReg.getNode())) break; if (AM.GV != 0 || AM.CP != 0 || AM.ES != 0 || AM.JT != -1) break; // If value is available in a register both base and index components have // been picked, we can't fit the result available in the register in the // addressing mode. Duplicate GlobalAddress or ConstantPool as displacement. if (!AlreadySelected || (AM.Base.Reg.getNode() && AM.IndexReg.getNode())) { SDValue N0 = N.getOperand(0); if (GlobalAddressSDNode *G = dyn_cast(N0)) { GlobalValue *GV = G->getGlobal(); AM.GV = GV; AM.Disp += G->getOffset(); AM.isRIPRel = TM.getRelocationModel() != Reloc::Static && Subtarget->isPICStyleRIPRel(); return false; } else if (ConstantPoolSDNode *CP = dyn_cast(N0)) { AM.CP = CP->getConstVal(); AM.Align = CP->getAlignment(); AM.Disp += CP->getOffset(); AM.isRIPRel = TM.getRelocationModel() != Reloc::Static && Subtarget->isPICStyleRIPRel(); return false; } else if (ExternalSymbolSDNode *S =dyn_cast(N0)) { AM.ES = S->getSymbol(); AM.isRIPRel = TM.getRelocationModel() != Reloc::Static && Subtarget->isPICStyleRIPRel(); return false; } else if (JumpTableSDNode *J = dyn_cast(N0)) { AM.JT = J->getIndex(); AM.isRIPRel = TM.getRelocationModel() != Reloc::Static && Subtarget->isPICStyleRIPRel(); return false; } } break; } case ISD::FrameIndex: if (AM.BaseType == X86ISelAddressMode::RegBase && AM.Base.Reg.getNode() == 0) { AM.BaseType = X86ISelAddressMode::FrameIndexBase; AM.Base.FrameIndex = cast(N)->getIndex(); return false; } break; case ISD::SHL: if (AlreadySelected || AM.IndexReg.getNode() != 0 || AM.Scale != 1 || AM.isRIPRel) break; if (ConstantSDNode *CN = dyn_cast(N.getNode()->getOperand(1))) { unsigned Val = CN->getZExtValue(); if (Val == 1 || Val == 2 || Val == 3) { AM.Scale = 1 << Val; SDValue ShVal = N.getNode()->getOperand(0); // Okay, we know that we have a scale by now. However, if the scaled // value is an add of something and a constant, we can fold the // constant into the disp field here. if (ShVal.getNode()->getOpcode() == ISD::ADD && ShVal.hasOneUse() && isa(ShVal.getNode()->getOperand(1))) { AM.IndexReg = ShVal.getNode()->getOperand(0); ConstantSDNode *AddVal = cast(ShVal.getNode()->getOperand(1)); uint64_t Disp = AM.Disp + (AddVal->getZExtValue() << Val); if (isInt32(Disp)) AM.Disp = Disp; else AM.IndexReg = ShVal; } else { AM.IndexReg = ShVal; } return false; } break; } case ISD::SMUL_LOHI: case ISD::UMUL_LOHI: // A mul_lohi where we need the low part can be folded as a plain multiply. if (N.getResNo() != 0) break; // FALL THROUGH case ISD::MUL: // X*[3,5,9] -> X+X*[2,4,8] if (!AlreadySelected && AM.BaseType == X86ISelAddressMode::RegBase && AM.Base.Reg.getNode() == 0 && AM.IndexReg.getNode() == 0 && !AM.isRIPRel) { if (ConstantSDNode *CN = dyn_cast(N.getNode()->getOperand(1))) if (CN->getZExtValue() == 3 || CN->getZExtValue() == 5 || CN->getZExtValue() == 9) { AM.Scale = unsigned(CN->getZExtValue())-1; SDValue MulVal = N.getNode()->getOperand(0); SDValue Reg; // Okay, we know that we have a scale by now. However, if the scaled // value is an add of something and a constant, we can fold the // constant into the disp field here. if (MulVal.getNode()->getOpcode() == ISD::ADD && MulVal.hasOneUse() && isa(MulVal.getNode()->getOperand(1))) { Reg = MulVal.getNode()->getOperand(0); ConstantSDNode *AddVal = cast(MulVal.getNode()->getOperand(1)); uint64_t Disp = AM.Disp + AddVal->getZExtValue() * CN->getZExtValue(); if (isInt32(Disp)) AM.Disp = Disp; else Reg = N.getNode()->getOperand(0); } else { Reg = N.getNode()->getOperand(0); } AM.IndexReg = AM.Base.Reg = Reg; return false; } } break; case ISD::ADD: if (!AlreadySelected) { X86ISelAddressMode Backup = AM; if (!MatchAddress(N.getNode()->getOperand(0), AM, false, Depth+1) && !MatchAddress(N.getNode()->getOperand(1), AM, false, Depth+1)) return false; AM = Backup; if (!MatchAddress(N.getNode()->getOperand(1), AM, false, Depth+1) && !MatchAddress(N.getNode()->getOperand(0), AM, false, Depth+1)) return false; AM = Backup; } break; case ISD::OR: // Handle "X | C" as "X + C" iff X is known to have C bits clear. if (AlreadySelected) break; if (ConstantSDNode *CN = dyn_cast(N.getOperand(1))) { X86ISelAddressMode Backup = AM; // Start with the LHS as an addr mode. if (!MatchAddress(N.getOperand(0), AM, false) && // Address could not have picked a GV address for the displacement. AM.GV == NULL && // On x86-64, the resultant disp must fit in 32-bits. isInt32(AM.Disp + CN->getSignExtended()) && // Check to see if the LHS & C is zero. CurDAG->MaskedValueIsZero(N.getOperand(0), CN->getAPIntValue())) { AM.Disp += CN->getZExtValue(); return false; } AM = Backup; } break; case ISD::AND: { // Handle "(x << C1) & C2" as "(X & (C2>>C1)) << C1" if safe and if this // allows us to fold the shift into this addressing mode. if (AlreadySelected) break; SDValue Shift = N.getOperand(0); if (Shift.getOpcode() != ISD::SHL) break; // Scale must not be used already. if (AM.IndexReg.getNode() != 0 || AM.Scale != 1) break; // Not when RIP is used as the base. if (AM.isRIPRel) break; ConstantSDNode *C2 = dyn_cast(N.getOperand(1)); ConstantSDNode *C1 = dyn_cast(Shift.getOperand(1)); if (!C1 || !C2) break; // Not likely to be profitable if either the AND or SHIFT node has more // than one use (unless all uses are for address computation). Besides, // isel mechanism requires their node ids to be reused. if (!N.hasOneUse() || !Shift.hasOneUse()) break; // Verify that the shift amount is something we can fold. unsigned ShiftCst = C1->getZExtValue(); if (ShiftCst != 1 && ShiftCst != 2 && ShiftCst != 3) break; // Get the new AND mask, this folds to a constant. SDValue NewANDMask = CurDAG->getNode(ISD::SRL, N.getValueType(), SDValue(C2, 0), SDValue(C1, 0)); SDValue NewAND = CurDAG->getNode(ISD::AND, N.getValueType(), Shift.getOperand(0), NewANDMask); NewANDMask.getNode()->setNodeId(Shift.getNode()->getNodeId()); NewAND.getNode()->setNodeId(N.getNode()->getNodeId()); AM.Scale = 1 << ShiftCst; AM.IndexReg = NewAND; return false; } } return MatchAddressBase(N, AM, isRoot, Depth); } /// MatchAddressBase - Helper for MatchAddress. Add the specified node to the /// specified addressing mode without any further recursion. bool X86DAGToDAGISel::MatchAddressBase(SDValue N, X86ISelAddressMode &AM, bool isRoot, unsigned Depth) { // Is the base register already occupied? if (AM.BaseType != X86ISelAddressMode::RegBase || AM.Base.Reg.getNode()) { // If so, check to see if the scale index register is set. if (AM.IndexReg.getNode() == 0 && !AM.isRIPRel) { AM.IndexReg = N; AM.Scale = 1; return false; } // Otherwise, we cannot select it. return true; } // Default, generate it as a register. AM.BaseType = X86ISelAddressMode::RegBase; AM.Base.Reg = N; return false; } /// SelectAddr - returns true if it is able pattern match an addressing mode. /// It returns the operands which make up the maximal addressing mode it can /// match by reference. bool X86DAGToDAGISel::SelectAddr(SDValue Op, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp) { X86ISelAddressMode AM; if (MatchAddress(N, AM)) return false; MVT VT = N.getValueType(); if (AM.BaseType == X86ISelAddressMode::RegBase) { if (!AM.Base.Reg.getNode()) AM.Base.Reg = CurDAG->getRegister(0, VT); } if (!AM.IndexReg.getNode()) AM.IndexReg = CurDAG->getRegister(0, VT); getAddressOperands(AM, Base, Scale, Index, Disp); return true; } /// isZeroNode - Returns true if Elt is a constant zero or a floating point /// constant +0.0. static inline bool isZeroNode(SDValue Elt) { return ((isa(Elt) && cast(Elt)->getZExtValue() == 0) || (isa(Elt) && cast(Elt)->getValueAPF().isPosZero())); } /// SelectScalarSSELoad - Match a scalar SSE load. In particular, we want to /// match a load whose top elements are either undef or zeros. The load flavor /// is derived from the type of N, which is either v4f32 or v2f64. bool X86DAGToDAGISel::SelectScalarSSELoad(SDValue Op, SDValue Pred, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &InChain, SDValue &OutChain) { if (N.getOpcode() == ISD::SCALAR_TO_VECTOR) { InChain = N.getOperand(0).getValue(1); if (ISD::isNON_EXTLoad(InChain.getNode()) && InChain.getValue(0).hasOneUse() && N.hasOneUse() && CanBeFoldedBy(N.getNode(), Pred.getNode(), Op.getNode())) { LoadSDNode *LD = cast(InChain); if (!SelectAddr(Op, LD->getBasePtr(), Base, Scale, Index, Disp)) return false; OutChain = LD->getChain(); return true; } } // Also handle the case where we explicitly require zeros in the top // elements. This is a vector shuffle from the zero vector. if (N.getOpcode() == X86ISD::VZEXT_MOVL && N.getNode()->hasOneUse() && // Check to see if the top elements are all zeros (or bitcast of zeros). N.getOperand(0).getOpcode() == ISD::SCALAR_TO_VECTOR && N.getOperand(0).getNode()->hasOneUse() && ISD::isNON_EXTLoad(N.getOperand(0).getOperand(0).getNode()) && N.getOperand(0).getOperand(0).hasOneUse()) { // Okay, this is a zero extending load. Fold it. LoadSDNode *LD = cast(N.getOperand(0).getOperand(0)); if (!SelectAddr(Op, LD->getBasePtr(), Base, Scale, Index, Disp)) return false; OutChain = LD->getChain(); InChain = SDValue(LD, 1); return true; } return false; } /// SelectLEAAddr - it calls SelectAddr and determines if the maximal addressing /// mode it matches can be cost effectively emitted as an LEA instruction. bool X86DAGToDAGISel::SelectLEAAddr(SDValue Op, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp) { X86ISelAddressMode AM; if (MatchAddress(N, AM)) return false; MVT VT = N.getValueType(); unsigned Complexity = 0; if (AM.BaseType == X86ISelAddressMode::RegBase) if (AM.Base.Reg.getNode()) Complexity = 1; else AM.Base.Reg = CurDAG->getRegister(0, VT); else if (AM.BaseType == X86ISelAddressMode::FrameIndexBase) Complexity = 4; if (AM.IndexReg.getNode()) Complexity++; else AM.IndexReg = CurDAG->getRegister(0, VT); // Don't match just leal(,%reg,2). It's cheaper to do addl %reg, %reg, or with // a simple shift. if (AM.Scale > 1) Complexity++; // FIXME: We are artificially lowering the criteria to turn ADD %reg, $GA // to a LEA. This is determined with some expermentation but is by no means // optimal (especially for code size consideration). LEA is nice because of // its three-address nature. Tweak the cost function again when we can run // convertToThreeAddress() at register allocation time. if (AM.GV || AM.CP || AM.ES || AM.JT != -1) { // For X86-64, we should always use lea to materialize RIP relative // addresses. if (Subtarget->is64Bit()) Complexity = 4; else Complexity += 2; } if (AM.Disp && (AM.Base.Reg.getNode() || AM.IndexReg.getNode())) Complexity++; if (Complexity > 2) { getAddressOperands(AM, Base, Scale, Index, Disp); return true; } return false; } bool X86DAGToDAGISel::TryFoldLoad(SDValue P, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp) { if (ISD::isNON_EXTLoad(N.getNode()) && N.hasOneUse() && CanBeFoldedBy(N.getNode(), P.getNode(), P.getNode())) return SelectAddr(P, N.getOperand(1), Base, Scale, Index, Disp); return false; } /// getGlobalBaseReg - Output the instructions required to put the /// base address to use for accessing globals into a register. /// SDNode *X86DAGToDAGISel::getGlobalBaseReg() { assert(!Subtarget->is64Bit() && "X86-64 PIC uses RIP relative addressing"); if (!GlobalBaseReg) { // Insert the set of GlobalBaseReg into the first MBB of the function MachineFunction *MF = BB->getParent(); MachineBasicBlock &FirstMBB = MF->front(); MachineBasicBlock::iterator MBBI = FirstMBB.begin(); MachineRegisterInfo &RegInfo = MF->getRegInfo(); unsigned PC = RegInfo.createVirtualRegister(X86::GR32RegisterClass); const TargetInstrInfo *TII = TM.getInstrInfo(); // Operand of MovePCtoStack is completely ignored by asm printer. It's // only used in JIT code emission as displacement to pc. BuildMI(FirstMBB, MBBI, TII->get(X86::MOVPC32r), PC).addImm(0); // If we're using vanilla 'GOT' PIC style, we should use relative addressing // not to pc, but to _GLOBAL_ADDRESS_TABLE_ external if (TM.getRelocationModel() == Reloc::PIC_ && Subtarget->isPICStyleGOT()) { GlobalBaseReg = RegInfo.createVirtualRegister(X86::GR32RegisterClass); BuildMI(FirstMBB, MBBI, TII->get(X86::ADD32ri), GlobalBaseReg) .addReg(PC).addExternalSymbol("_GLOBAL_OFFSET_TABLE_"); } else { GlobalBaseReg = PC; } } return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode(); } static SDNode *FindCallStartFromCall(SDNode *Node) { if (Node->getOpcode() == ISD::CALLSEQ_START) return Node; assert(Node->getOperand(0).getValueType() == MVT::Other && "Node doesn't have a token chain argument!"); return FindCallStartFromCall(Node->getOperand(0).getNode()); } /// getTruncateTo8Bit - return an SDNode that implements a subreg based /// truncate of the specified operand to i8. This can be done with tablegen, /// except that this code uses MVT::Flag in a tricky way that happens to /// improve scheduling in some cases. SDNode *X86DAGToDAGISel::getTruncateTo8Bit(SDValue N0) { assert(!Subtarget->is64Bit() && "getTruncateTo8Bit is only needed on x86-32!"); SDValue SRIdx = CurDAG->getTargetConstant(1, MVT::i32); // SubRegSet 1 // Ensure that the source register has an 8-bit subreg on 32-bit targets unsigned Opc; MVT N0VT = N0.getValueType(); switch (N0VT.getSimpleVT()) { default: assert(0 && "Unknown truncate!"); case MVT::i16: Opc = X86::MOV16to16_; break; case MVT::i32: Opc = X86::MOV32to32_; break; } // The use of MVT::Flag here is not strictly accurate, but it helps // scheduling in some cases. N0 = SDValue(CurDAG->getTargetNode(Opc, N0VT, MVT::Flag, N0), 0); return CurDAG->getTargetNode(X86::EXTRACT_SUBREG, MVT::i8, N0, SRIdx, N0.getValue(1)); } SDNode *X86DAGToDAGISel::Select(SDValue N) { SDNode *Node = N.getNode(); MVT NVT = Node->getValueType(0); unsigned Opc, MOpc; unsigned Opcode = Node->getOpcode(); #ifndef NDEBUG DOUT << std::string(Indent, ' ') << "Selecting: "; DEBUG(Node->dump(CurDAG)); DOUT << "\n"; Indent += 2; #endif if (Node->isMachineOpcode()) { #ifndef NDEBUG DOUT << std::string(Indent-2, ' ') << "== "; DEBUG(Node->dump(CurDAG)); DOUT << "\n"; Indent -= 2; #endif return NULL; // Already selected. } switch (Opcode) { default: break; case X86ISD::GlobalBaseReg: return getGlobalBaseReg(); case ISD::ADD: { // Turn ADD X, c to MOV32ri X+c. This cannot be done with tblgen'd // code and is matched first so to prevent it from being turned into // LEA32r X+c. // In 64-bit small code size mode, use LEA to take advantage of // RIP-relative addressing. if (TM.getCodeModel() != CodeModel::Small) break; MVT PtrVT = TLI.getPointerTy(); SDValue N0 = N.getOperand(0); SDValue N1 = N.getOperand(1); if (N.getNode()->getValueType(0) == PtrVT && N0.getOpcode() == X86ISD::Wrapper && N1.getOpcode() == ISD::Constant) { unsigned Offset = (unsigned)cast(N1)->getZExtValue(); SDValue C(0, 0); // TODO: handle ExternalSymbolSDNode. if (GlobalAddressSDNode *G = dyn_cast(N0.getOperand(0))) { C = CurDAG->getTargetGlobalAddress(G->getGlobal(), PtrVT, G->getOffset() + Offset); } else if (ConstantPoolSDNode *CP = dyn_cast(N0.getOperand(0))) { C = CurDAG->getTargetConstantPool(CP->getConstVal(), PtrVT, CP->getAlignment(), CP->getOffset()+Offset); } if (C.getNode()) { if (Subtarget->is64Bit()) { SDValue Ops[] = { CurDAG->getRegister(0, PtrVT), getI8Imm(1), CurDAG->getRegister(0, PtrVT), C }; return CurDAG->SelectNodeTo(N.getNode(), X86::LEA64r, MVT::i64, Ops, 4); } else return CurDAG->SelectNodeTo(N.getNode(), X86::MOV32ri, PtrVT, C); } } // Other cases are handled by auto-generated code. break; } case ISD::SMUL_LOHI: case ISD::UMUL_LOHI: { SDValue N0 = Node->getOperand(0); SDValue N1 = Node->getOperand(1); bool isSigned = Opcode == ISD::SMUL_LOHI; if (!isSigned) switch (NVT.getSimpleVT()) { default: assert(0 && "Unsupported VT!"); case MVT::i8: Opc = X86::MUL8r; MOpc = X86::MUL8m; break; case MVT::i16: Opc = X86::MUL16r; MOpc = X86::MUL16m; break; case MVT::i32: Opc = X86::MUL32r; MOpc = X86::MUL32m; break; case MVT::i64: Opc = X86::MUL64r; MOpc = X86::MUL64m; break; } else switch (NVT.getSimpleVT()) { default: assert(0 && "Unsupported VT!"); case MVT::i8: Opc = X86::IMUL8r; MOpc = X86::IMUL8m; break; case MVT::i16: Opc = X86::IMUL16r; MOpc = X86::IMUL16m; break; case MVT::i32: Opc = X86::IMUL32r; MOpc = X86::IMUL32m; break; case MVT::i64: Opc = X86::IMUL64r; MOpc = X86::IMUL64m; break; } unsigned LoReg, HiReg; switch (NVT.getSimpleVT()) { default: assert(0 && "Unsupported VT!"); case MVT::i8: LoReg = X86::AL; HiReg = X86::AH; break; case MVT::i16: LoReg = X86::AX; HiReg = X86::DX; break; case MVT::i32: LoReg = X86::EAX; HiReg = X86::EDX; break; case MVT::i64: LoReg = X86::RAX; HiReg = X86::RDX; break; } SDValue Tmp0, Tmp1, Tmp2, Tmp3; bool foldedLoad = TryFoldLoad(N, N1, Tmp0, Tmp1, Tmp2, Tmp3); // multiplty is commmutative if (!foldedLoad) { foldedLoad = TryFoldLoad(N, N0, Tmp0, Tmp1, Tmp2, Tmp3); if (foldedLoad) std::swap(N0, N1); } AddToISelQueue(N0); SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), LoReg, N0, SDValue()).getValue(1); if (foldedLoad) { AddToISelQueue(N1.getOperand(0)); AddToISelQueue(Tmp0); AddToISelQueue(Tmp1); AddToISelQueue(Tmp2); AddToISelQueue(Tmp3); SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, N1.getOperand(0), InFlag }; SDNode *CNode = CurDAG->getTargetNode(MOpc, MVT::Other, MVT::Flag, Ops, 6); InFlag = SDValue(CNode, 1); // Update the chain. ReplaceUses(N1.getValue(1), SDValue(CNode, 0)); } else { AddToISelQueue(N1); InFlag = SDValue(CurDAG->getTargetNode(Opc, MVT::Flag, N1, InFlag), 0); } // Copy the low half of the result, if it is needed. if (!N.getValue(0).use_empty()) { SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), LoReg, NVT, InFlag); InFlag = Result.getValue(2); ReplaceUses(N.getValue(0), Result); #ifndef NDEBUG DOUT << std::string(Indent-2, ' ') << "=> "; DEBUG(Result.getNode()->dump(CurDAG)); DOUT << "\n"; #endif } // Copy the high half of the result, if it is needed. if (!N.getValue(1).use_empty()) { SDValue Result; if (HiReg == X86::AH && Subtarget->is64Bit()) { // Prevent use of AH in a REX instruction by referencing AX instead. // Shift it down 8 bits. Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), X86::AX, MVT::i16, InFlag); InFlag = Result.getValue(2); Result = SDValue(CurDAG->getTargetNode(X86::SHR16ri, MVT::i16, Result, CurDAG->getTargetConstant(8, MVT::i8)), 0); // Then truncate it down to i8. SDValue SRIdx = CurDAG->getTargetConstant(1, MVT::i32); // SubRegSet 1 Result = SDValue(CurDAG->getTargetNode(X86::EXTRACT_SUBREG, MVT::i8, Result, SRIdx), 0); } else { Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), HiReg, NVT, InFlag); InFlag = Result.getValue(2); } ReplaceUses(N.getValue(1), Result); #ifndef NDEBUG DOUT << std::string(Indent-2, ' ') << "=> "; DEBUG(Result.getNode()->dump(CurDAG)); DOUT << "\n"; #endif } #ifndef NDEBUG Indent -= 2; #endif return NULL; } case ISD::SDIVREM: case ISD::UDIVREM: { SDValue N0 = Node->getOperand(0); SDValue N1 = Node->getOperand(1); bool isSigned = Opcode == ISD::SDIVREM; if (!isSigned) switch (NVT.getSimpleVT()) { default: assert(0 && "Unsupported VT!"); case MVT::i8: Opc = X86::DIV8r; MOpc = X86::DIV8m; break; case MVT::i16: Opc = X86::DIV16r; MOpc = X86::DIV16m; break; case MVT::i32: Opc = X86::DIV32r; MOpc = X86::DIV32m; break; case MVT::i64: Opc = X86::DIV64r; MOpc = X86::DIV64m; break; } else switch (NVT.getSimpleVT()) { default: assert(0 && "Unsupported VT!"); case MVT::i8: Opc = X86::IDIV8r; MOpc = X86::IDIV8m; break; case MVT::i16: Opc = X86::IDIV16r; MOpc = X86::IDIV16m; break; case MVT::i32: Opc = X86::IDIV32r; MOpc = X86::IDIV32m; break; case MVT::i64: Opc = X86::IDIV64r; MOpc = X86::IDIV64m; break; } unsigned LoReg, HiReg; unsigned ClrOpcode, SExtOpcode; switch (NVT.getSimpleVT()) { default: assert(0 && "Unsupported VT!"); case MVT::i8: LoReg = X86::AL; HiReg = X86::AH; ClrOpcode = 0; SExtOpcode = X86::CBW; break; case MVT::i16: LoReg = X86::AX; HiReg = X86::DX; ClrOpcode = X86::MOV16r0; SExtOpcode = X86::CWD; break; case MVT::i32: LoReg = X86::EAX; HiReg = X86::EDX; ClrOpcode = X86::MOV32r0; SExtOpcode = X86::CDQ; break; case MVT::i64: LoReg = X86::RAX; HiReg = X86::RDX; ClrOpcode = X86::MOV64r0; SExtOpcode = X86::CQO; break; } SDValue Tmp0, Tmp1, Tmp2, Tmp3; bool foldedLoad = TryFoldLoad(N, N1, Tmp0, Tmp1, Tmp2, Tmp3); SDValue InFlag; if (NVT == MVT::i8 && !isSigned) { // Special case for div8, just use a move with zero extension to AX to // clear the upper 8 bits (AH). SDValue Tmp0, Tmp1, Tmp2, Tmp3, Move, Chain; if (TryFoldLoad(N, N0, Tmp0, Tmp1, Tmp2, Tmp3)) { SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, N0.getOperand(0) }; AddToISelQueue(N0.getOperand(0)); AddToISelQueue(Tmp0); AddToISelQueue(Tmp1); AddToISelQueue(Tmp2); AddToISelQueue(Tmp3); Move = SDValue(CurDAG->getTargetNode(X86::MOVZX16rm8, MVT::i16, MVT::Other, Ops, 5), 0); Chain = Move.getValue(1); ReplaceUses(N0.getValue(1), Chain); } else { AddToISelQueue(N0); Move = SDValue(CurDAG->getTargetNode(X86::MOVZX16rr8, MVT::i16, N0), 0); Chain = CurDAG->getEntryNode(); } Chain = CurDAG->getCopyToReg(Chain, X86::AX, Move, SDValue()); InFlag = Chain.getValue(1); } else { AddToISelQueue(N0); InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), LoReg, N0, SDValue()).getValue(1); if (isSigned) { // Sign extend the low part into the high part. InFlag = SDValue(CurDAG->getTargetNode(SExtOpcode, MVT::Flag, InFlag), 0); } else { // Zero out the high part, effectively zero extending the input. SDValue ClrNode = SDValue(CurDAG->getTargetNode(ClrOpcode, NVT), 0); InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), HiReg, ClrNode, InFlag).getValue(1); } } if (foldedLoad) { AddToISelQueue(N1.getOperand(0)); AddToISelQueue(Tmp0); AddToISelQueue(Tmp1); AddToISelQueue(Tmp2); AddToISelQueue(Tmp3); SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, N1.getOperand(0), InFlag }; SDNode *CNode = CurDAG->getTargetNode(MOpc, MVT::Other, MVT::Flag, Ops, 6); InFlag = SDValue(CNode, 1); // Update the chain. ReplaceUses(N1.getValue(1), SDValue(CNode, 0)); } else { AddToISelQueue(N1); InFlag = SDValue(CurDAG->getTargetNode(Opc, MVT::Flag, N1, InFlag), 0); } // Copy the division (low) result, if it is needed. if (!N.getValue(0).use_empty()) { SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), LoReg, NVT, InFlag); InFlag = Result.getValue(2); ReplaceUses(N.getValue(0), Result); #ifndef NDEBUG DOUT << std::string(Indent-2, ' ') << "=> "; DEBUG(Result.getNode()->dump(CurDAG)); DOUT << "\n"; #endif } // Copy the remainder (high) result, if it is needed. if (!N.getValue(1).use_empty()) { SDValue Result; if (HiReg == X86::AH && Subtarget->is64Bit()) { // Prevent use of AH in a REX instruction by referencing AX instead. // Shift it down 8 bits. Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), X86::AX, MVT::i16, InFlag); InFlag = Result.getValue(2); Result = SDValue(CurDAG->getTargetNode(X86::SHR16ri, MVT::i16, Result, CurDAG->getTargetConstant(8, MVT::i8)), 0); // Then truncate it down to i8. SDValue SRIdx = CurDAG->getTargetConstant(1, MVT::i32); // SubRegSet 1 Result = SDValue(CurDAG->getTargetNode(X86::EXTRACT_SUBREG, MVT::i8, Result, SRIdx), 0); } else { Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), HiReg, NVT, InFlag); InFlag = Result.getValue(2); } ReplaceUses(N.getValue(1), Result); #ifndef NDEBUG DOUT << std::string(Indent-2, ' ') << "=> "; DEBUG(Result.getNode()->dump(CurDAG)); DOUT << "\n"; #endif } #ifndef NDEBUG Indent -= 2; #endif return NULL; } case ISD::SIGN_EXTEND_INREG: { MVT SVT = cast(Node->getOperand(1))->getVT(); if (SVT == MVT::i8 && !Subtarget->is64Bit()) { SDValue N0 = Node->getOperand(0); AddToISelQueue(N0); SDValue TruncOp = SDValue(getTruncateTo8Bit(N0), 0); unsigned Opc = 0; switch (NVT.getSimpleVT()) { default: assert(0 && "Unknown sign_extend_inreg!"); case MVT::i16: Opc = X86::MOVSX16rr8; break; case MVT::i32: Opc = X86::MOVSX32rr8; break; } SDNode *ResNode = CurDAG->getTargetNode(Opc, NVT, TruncOp); #ifndef NDEBUG DOUT << std::string(Indent-2, ' ') << "=> "; DEBUG(TruncOp.getNode()->dump(CurDAG)); DOUT << "\n"; DOUT << std::string(Indent-2, ' ') << "=> "; DEBUG(ResNode->dump(CurDAG)); DOUT << "\n"; Indent -= 2; #endif return ResNode; } break; } case ISD::TRUNCATE: { if (NVT == MVT::i8 && !Subtarget->is64Bit()) { SDValue Input = Node->getOperand(0); AddToISelQueue(Node->getOperand(0)); SDNode *ResNode = getTruncateTo8Bit(Input); #ifndef NDEBUG DOUT << std::string(Indent-2, ' ') << "=> "; DEBUG(ResNode->dump(CurDAG)); DOUT << "\n"; Indent -= 2; #endif return ResNode; } break; } case ISD::DECLARE: { // Handle DECLARE nodes here because the second operand may have been // wrapped in X86ISD::Wrapper. SDValue Chain = Node->getOperand(0); SDValue N1 = Node->getOperand(1); SDValue N2 = Node->getOperand(2); if (!isa(N1)) break; int FI = cast(N1)->getIndex(); if (N2.getOpcode() == ISD::ADD && N2.getOperand(0).getOpcode() == X86ISD::GlobalBaseReg) N2 = N2.getOperand(1); if (N2.getOpcode() == X86ISD::Wrapper && isa(N2.getOperand(0))) { GlobalValue *GV = cast(N2.getOperand(0))->getGlobal(); SDValue Tmp1 = CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy()); SDValue Tmp2 = CurDAG->getTargetGlobalAddress(GV, TLI.getPointerTy()); AddToISelQueue(Chain); SDValue Ops[] = { Tmp1, Tmp2, Chain }; return CurDAG->getTargetNode(TargetInstrInfo::DECLARE, MVT::Other, Ops, 3); } break; } } SDNode *ResNode = SelectCode(N); #ifndef NDEBUG DOUT << std::string(Indent-2, ' ') << "=> "; if (ResNode == NULL || ResNode == N.getNode()) DEBUG(N.getNode()->dump(CurDAG)); else DEBUG(ResNode->dump(CurDAG)); DOUT << "\n"; Indent -= 2; #endif return ResNode; } bool X86DAGToDAGISel:: SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode, std::vector &OutOps) { SDValue Op0, Op1, Op2, Op3; switch (ConstraintCode) { case 'o': // offsetable ?? case 'v': // not offsetable ?? default: return true; case 'm': // memory if (!SelectAddr(Op, Op, Op0, Op1, Op2, Op3)) return true; break; } OutOps.push_back(Op0); OutOps.push_back(Op1); OutOps.push_back(Op2); OutOps.push_back(Op3); AddToISelQueue(Op0); AddToISelQueue(Op1); AddToISelQueue(Op2); AddToISelQueue(Op3); return false; } /// createX86ISelDag - This pass converts a legalized DAG into a /// X86-specific DAG, ready for instruction scheduling. /// FunctionPass *llvm::createX86ISelDag(X86TargetMachine &TM, bool Fast) { return new X86DAGToDAGISel(TM, Fast); }